From the earliest lessons pupils learn to make sense of the language of music through the idea of pattern and surprise. This is one of the best examples I can think of – from Cello Concerto No. 1 by Shostakovich.
Here is the first phrase – a 5-note motif: Shostakovich – Cello Concerto – Sample 1
Now, phrases 1 and 2 – same rhythm (making it a sequence) – change of pitch (distinguishing sequence from simple repetition): Shostakovich – Cello Concerto – Sample 2
Patterns usually break away on the third phrase and sure enough the space at the end of the 5-note pattern has been filled with a 6th note: Shostakovich – Cello Concerto – Sample 3
But there is is another über-surprise hot on the heels of that. What would you do next? This? Shostakovich – Cello Concerto – Sample 4